Hello, A yearly allocation for the LCRC cluster has been requested with the following updated information: Submitter/PI: Donald Sinclair Project Name: Lattice-QCD Division: HEP Project title: Lattice simulations of Conformal and Walking Technicolor. Associated funding: DOE Other Systems: NERSC Cray XT6, "Hopper" NERSC Cluster, "Carver" NICS Cray XT5, "Kraken" Science: We are using our simulation methods developed for lattice QCD to study extensions of the standard model of High Energy Physics, in which the Higgs sector is strongly interacting, and the Higgs fields are composites. This has become all the more relevant with the recent report of the discovery of a Higgs-like particle at the LHC at CERN. We are particularly interested in QCD-like theories whose pions play the role of the Higgs field in giving masses to the W and Z gauge bosons. Such theories are called Technicolor theories. We are particularly interested in Walking Technicolor theories, whose slowly evolving couplings evade some of the technical difficulties associated with the phenomenology of Technicolor and Extended Technicolor theories. Our initial studies are of the thermodynamics of such theories, since these provide a simple way of measuring the scales of confinement and of chiral symmetry breaking. Our previous work on N_t=4,6,8 lattices (for 2 flavours) has indicated that larger N_t's are needed to access continuum physics. For 3 flavours, our work on N_t=4,6 and preliminary work on N_t=8 lattices also suggest the need for larger N_t's. Project description: We perform simulations to evaluate the functional integrals of QCD-like theories formulated on a discrete space-time lattice, to enable determination of the non-perturbative aspects these theories. These include the properties of these theories at non-zero temperature, including the scales of confinement and chiral symmetry breaking, and such zero temperature properties as spectra (including the Higgs mass), decay constants and the running of the gauge coupling constant. We are particularly interested in those theories where the coupling constant evolves very slowly, since these are candidate 'Walking Technicolor' theories. Related to these are theories with an infrared fixed point (conformal field theories). Our first goal is to differentiate between these two different types of behaviour for candidate theories. We are performing simulations of QCD-like theories which are models for Walking or Conformal Technicolor. We have been studying theories which are essentially QCD but with colour-sextet rather than colour-triplet quarks. We hope to measure the running of the QCD coupling constant. For 2 or 3 flavours, 2-loop perturbation theory predicts an infrared fixed point. For 2 flavours, it is possible that a chiral condensate forms before this fixed point is reached. If so, the fixed point is avoided, the theory is confining, and chiral symmetry breaks spontaneously. However, there is a region where the coupling constant evolves very slowly. These are the properties required for a walking technicolor theory. Simulations we have performed so far at finite temperature suggest that this theory might walk. This is an ongoing program at NERSC. We are also running small-lattice simulations of the 3-flavour theory, which we expect to have conformal, rather than walking behaviour on Fusion, for comparison. If we are correct, the properties of the 2 and 3 flavour theories should look rather different. In addition to finishing these 3-flavour runs on Fusion, we plan to extend some earlier 2-flavour work on Fusion on a 24^3*8 lattice to compare with our work at NERSC on 16^3*8 lattices. These 24^3*8 runs will be of a much more limited scope than those on 16^3*8 lattices, and are needed to check that finite size effects are under control. Our sextet quark codes are based on our earlier triplet quark codes and use the RHMC simulation method. The Rational Hybrid Monte Carlo (RHMC) is a stochastic molecular dynamics algorithm. The functional integral of QCD is written as a partition function of a classical field theory evolving in a fictitious time. The determinant of the Dirac operator raised to a fractional power is calculated by introducing bosonic fields (pseudofermions), and sandwiching this Dirac operator raised to minus said fractional power between them. This fractional power of the Dirac operator is approximated to machine accuracy by a rational approximation. After defining this this theory on a discrete space-time lattice, the inversions required by the partial-fraction expansion of the rational approximation are performed using Krylov space methods, in particular a multi-shift extension of the conjugate gradient algorithm. A global Metropolis Monte-Carlo accept/reject step applied at the end of each trajectory removes discretization errors introduced by the numerical integration of these stochastic equations of motion. We parallelize the code by assigning a fixed number of adjacent lattice sites to each MPI task. Network bandwidth ultimately limits how small a chunk of the lattice can be assigned to each task. Experience with benchmarking this code on a variety of lattice sizes indicates that we should expect a performance of approximately 3 Gflops/core for a 24^3*8 lattice running on 192 cores, i.e. around 550 to 600 Gflops. In each case we have checked, this per core performance remains nearly constant as the number of cores is varied, so that maximum throughput is achieved at the largest number of cores allowed by the current implementation (in this case 192). Project URL: http://www.hep.anl.gov/dks Current FY Hours Used: undetermined amount New FY Requested allocation: 975000 Q1: 350000 Q2: 300000 Q3: 200000 Q4: 125000 Justification: The per core performance for the 24^3*8 runs is approximately 3 Gflops on 192 cores. Althought we have not performed such a detailed analysis as for the 24^3*12 lattice, we expect at worst a linear speedup from the minimum number of cores (8) to the maximum number of cores (192). We note that the single node environment -- size and shape of the sublattice and communication pattern -- is identical for these 2 lattice sizes, which is why a separate performance analysis is unnecessary. This code has been running effectively on Fusion since it was released to the user community. We will be concentrating on the 2-flavour runs on 24^3*8 lattices with m=0.0025 on Fusion. Each run is expected to take approximately 60 wallclock-hours, and we are budgeting for 80 such runs. We are not providing detailed scaling analysis, since this was provided in previous years, and the code is unchanged. The main enhancement we have planned for this year is to rearrange the task to node assignments to assign a 24^2*4*2 section of the lattice to each node, rather than the default 24^2*8*1 section, by setting MPICH_RANK_REORDER_METHOD=3 and providing an appropriate MPICH_RANK_ORDER file. This will reduce the communication overhead. Any reduction of CPU time obtained by this enhancement will be used to finish our current project on a 16^3*8 lattice using 128 cores. Thank You, The LCRC Accounts System